Automatic power transmitting mechanism



- 2 Dec. 6, 1938. D E T 2,138,980

AUTOMATIC POWER TRANSMITTING MECHANISM Original Filed July 17, 1933 ZIP53.525135 w 4/ J7 6d 47 25 efwga Z fag 62? 4a I I q a 9% MM PatentedDec. 6, 1938 UNITED STATES nsect PATENT OFFECE AUTOMATIO POWERTRANSMITTING MECHANISM Divided and this application November 20, 1935,Serial No. 50,794

7 Claims.

The present invention relates to automatic power transmitting mechanismsand it is more particularly concerned with centrifugally operatingclutches.

This invention aims to provide a centrifugal clutch having means foryieldingly restraining the centrifugal elements against operation inresponse to centrifugal force to thereby delay the engaging action ofthe clutch, and although clutches of this general character have beenheretofore proposed, they have not proved altogether satisfactory, andmy invention aims to provide a clutch which is so designed as toovercome all of the defects of such prior clutches.

This application is a division of my copending application Serial No.680,857, filed July 17, 1933, (which has now matured into Patent No.2,045,611 dated June 30, 1936) and in that application I have shown theclutch of this invention in combination with an automatic transmission.The clutch of this invention, while particularly valuable in anautomatic transmission, is not limited to such use, and for this reason,and also in order to simplify the disclosure of this application, thedriving parts of the clutch will be described as coupled to an engine orother prime mover and the driven parts as connected to a driven shaft orother load. Accordingly, no reference will be made to the automatictransmission of my copending application.

It is a primary object of this invention to provide automatic clutchmechanisms of the character wherein frictional members are adapted to bebrought into engagement under the influence of mechanism that isresponsive to the speed of one of the members; with novel means fordelaying the action of the speed responsive mechanism whereby engagementof the frictional members under the influence of the speed responsivemechanism is confined to the upper part of the operating speed range ofthe frictional members, and pressure is built up comparatively rapidlybetween them when the members are accelerated through their upper speedrange.

Another object of my invention is to provide automatic clutch mechanismsof the type wherein a speed responsive mechanism is utilized to bringdisc-like frictional members into engagement; with a novel mechanism formodifying the action of the speed responsive mechanism so as to producea predetermined rate of pressure buildup between the frictional memberswhen one of the latter is accelerated through a certain speed range.

Another object of my invention resides in the provision of automaticclutch mechanisms of the type wherein a speed responsive mechanism isadapted to bring frictional members into engagement; with novel meansfor simultaneously retarding the action of the speed responsivemechanism so that the pressure builds up between the frictional membersat a rate that is different from the rate of acceleration of the latter.

Further objects of the invention will appear in the followingdescription when considered in connection with the accompanying drawing,and from the appended claims.

In the drawing:

Figure l is a longitudinal sectional view of a preferred embodiment ofthe invention.

Figure 2 is a frag-mental view in section illustrating the holdback boltassembly forming a part of the invention.

Figure 3 is a view similar to Figure 2 but shows a modified form of theinvention.

With continued reference to the drawing in which like referencecharacters are employed to indicate like parts throughout the severalviews, II indicates a driven shaft about one portion of which isconcentrically disposed a driving shaft l2 which receives torque from asleeve l3 by means of splines I4. Bushings I5 are provided forsupporting driving shaft I2 for rotation relative to the driven shaft,and oil returning grooves I6 are provided on the driving shaft forreturning to bushings I5 any lubricant which tends to leak thereby.Sleeve I3 is journalled by means of a bearing assembly I! within asupporting member I8 which is secured in any suitable manner (not shown)to the clutch housing I9.

flange portion 2| which contacts driving shaft I2 and which is providedwith oil returning grooves 22 for returning to bearings I'I anylubricant tending to leak thereby.

The forward end of driving shaft I2 is provided with a radiallyextending flange 23, to which is secured by means of bolts 24, aflywheel 25.

A hub 26, carrying a disc 21, is splined to a sleeve 28, and the latteris rigidly secured against ings 35 and 36 respectively which may consistof Supporting 3 member I8 is provided with a radially extending anymaterial that has the required characteristics to give the correctfrictional gripping force, and at the same time has wearing qualitiesadapting it for this purpose. I prefer, however, to use the types ofmaterial which in practice have given very satisfactory results in anautomatic slipping drive and clutch mechanism of the Powerflo type.Frictional facings 35 and 36 may be secured to disc 21 in any suitablemanner, as for instance by rivets or the like.

Facing 35 secured to disc 21 cooperates with the flat face of flywheel25 and is adapted to be engaged and frictionally driven thereby. Facing36 provided on disc 21 cooperates with a plate 31, which will behereinafter termed the automatic plate for the reason that it isautomatically actuated and is adapted to engage and clamp driven member21 between it and the flat face of the flywheel. Disc 21, along with hub26 and facings 35 and 36, constitute the driven member, and this entiredriven assembly will be hereinafter termed driven member 21 for sake ofbrevity. Plate 31 is of substantial thickness so that it may possess asuflicient degree of rigidity to prevent undesirable distortion andwarpage thereof during operating conditions.

As seen in Figure 2, a cover member 38 is secured to the flywheel bymeans of cap screws 39. Before cover 38 is secured to the flywheel,however, spacer members 4| are preferably inserted between theircooperating surfaces to space the cover from the flywheel for a purposethat will presently appear. Secured to the inner walls of cover 38 bymeans of rivets 42 or the like, are preferably three symmetricallyarranged driving lug or key members 43. Key members 83 are received in,and cooperate with the walls of recesses 44 formed in automatic plate 31to establish a driving connection between flywheel 25 and the automaticplate.

Disposed parallel to plate 31 is a plate 41, and it will be hereinafterreferred to as a reaction plate because it takes the reaction of thespeedresponsive mecham'sm in a manner to be presently described.Reaction plate 41 is driven by automatic plate 3? through the medium ofa plurality of cap screws 48. Referring particularly to Figure 2, eachcap screw 48 is provided with a reduced end 49 which is threaded intoautomatic plate 31, and the thread employed is preferably of theDardelet or other self locking type so as to prevent the cap screws fromworking loose in operation. Cap screws 48 extend through, and lie inslidable driving engagement with the walls of recesses 5| formed inreaction plate 41, and are encircled by washers 52 and compressionsprings 53. Springs 53 act against the heads of screws 48 and reactagainst plate 4? to thereby urge the automatic and reaction platestoward each other at all times, and they will be hereinafter referred toas hold-back springs.

The hold-back spring assemblies are preferably symmetrically disposed inpairs about the periphery of the plates, and in the present instance sixare employed, but it is to be understood that more or less than sixproperly designed holdback spring assemblies may be used if desiredwithout in any way departing from the spirit of my invention. Thehold-back assemblies accordingly establish a driving connection betweenthe automatic and reaction plates, and at the same time resiliently urgethem toward each other.

Reaction plate 81 is constantly urged toward the flywheel by a pluralityof compression springs 51 which act against the reaction plate and reactagainst the inner surface of cover 38.

The automatic and reaction plates may be actuated away from each otherby any suitable speed-responsive mechanism, to produce clutchengagement, but in the present embodiment of my invention it preferablytakes the form of centrifugally operable mechanism. Preferably .threeweight levers 6| having integrally formed heads 62 are symmetricallyarranged between the pairs of pressure springs 51 and have their heads62 received in rectangular recesses 63 formed in automatic plate 31.Levers 6! are provided with threaded studs 64 upon which are mountedweight elements 66 which are secured in place by means of nuts 6?threaded on the ends of studs 64.

Levers 6| are of substantial width and extend through recesses 73 formedin reaction plate 41. Heads 62 are provided with flat faces 14 thatnormally abut the bottoms of recesses 63 when the driving shaft isoperating at or below idling speed and are also provided with reactionfaces 16 which abut the face of reaction plate 4! at all times, and aredesigned for fulcruming engagement therewith during operation of theweights.

Heads 62 have their outer sides relieved to provide knife-like edges 13which are adapted to rock or pivot in the dihedral angles defined by thebottom and outer faces of recesses 63 formed in automatic plate 31.

When shaft I2 is stationary, or is operating at or below a speedcorresponding substantially to the idling speed of the prime moveremployed to drive it, the parts assume the positions in which they areshown in Figure 1. Heads 62 of levers 6| are clamped between plates 3'!and 41, under the influence of springs 53 acting against plate 4'! andcap screws 48.

Mounted in plate 41 and preferably symmetrically disposed between theweight assemblies are a plurality of bolts 82. Castle nuts. 85 arethreaded on bolts 82 and are adapted tobe held in adjusted positionsthereon by means of cotter pins 86. Hardened washers 81 are disposed onbolts 82 and cooperate with three clutch fingers 88 to produce movementof plate 41 away from the flywheel. Fingers 88 are pivoted on pins 89secured in brackets 92 which are mounted against Movement of the innerends of fingers 88 to the right in Figure 1, through the intermediary ofbolts 82, causes movement of plate 41 away from the flywheel against theaction springs 51. Movement of the reaction plate produces similarmovement of plate 31 because the hold-back assemblies hold the twoplates in unitary relationship at all times. Fingers 88 are adapted tobe actuated in this manner by means of a throwout assembly that will nowbe described.

Cooperating with curved faces H33 formed on levers 88 is a throwoutassembly consisting of a sleeve member I84 which is mounted for axialmovement on shaft H by means of a self-lubricating washer Hi5. Securedto sleeve 104 in any desired manner is a ball race E86. Disposed betweenball race I86 and an outer ball race #01 are a plurality ofanti-friction balls I88 and the bearing is designed to take a thrustload that is one hundred percent of the radial load. Secured to theoutside of race I01 are hardened stampings I09 which define a greasechamber.

A stamping I I2 is provided to operate as a dirt slinger to keep thedirt from working into the grease reservoir between stamping I03 andrace I06.

Although I prefer to use a bearing assembly of the character justdescribed, it is to be understood that any other suitable constructionmay be used without departing from the spirit of the present invention.

Adapted to cooperate with a flange I I3 formed on sleeve I04 is athrowout fork H4, which is secured to a shaft II5 journalled in housingI3. Fork I I4 is provided with curved faces I I6 which are adapted tocontact flange II3. Shaft II5 extends outwardly of housing I3 and isadapted to be actuated by a clutch pedal or lever (not shown).

Reaction plate 41 is provided with a flanged inner periphery I2I whichdefines a bearing I22.

- Slidably mounted for axial movement in bearing I22 and the flange incover 38, is a preferably cylindrical sheet metal sleeve member I23which is provided with a preferably annular corrugation I24. Levers 88extend through slots I25 formed in sleeve I23 and serve to prevent thelatter from being angularly displaced with respect to cover 38 andreaction plate 41 during operation of the mechanism. Cooperating withcorrugation I24 are balls I26 which are preferably three in number andare slidably mounted in recesses I21 located in plate 41. Balls I26 areurged to ward sleeve I23 by compression springs I23 which react againstpins I30 secured in plate 41.

Sleeve I23 is further provided with tongues I3I which seat in recessesI32 formed in Weights 66 and which serve to yieldingly resist operationof the latter in a manner that will hereinafter be described.

Springs 51 constantly urge plates 31 and 41 toward engaging position andin order to maintain the clutch disengaged when the driving shaft isstationary or is operating below the predetermined engaging speed alatch mechanism of any desired form may be used to hold the throwoutmechanism in automatic position, but in Figure 1, I have shown the latchmechanism disclosed 1n Patent No. 1,822,716 to H. H. Vail, dated Septem-I ber 8, 1931 as being associated with the clutch of this invention. I

Cooperating with fork H4 is the flange I4I of sleeve I42, which ismounted for axial sliding movement upon a supporting sleeve I43. SleeveI42 is keyed against rotative movement on mem ber I43 by any suitablemeans (not shown) and member I43 is stationarily supported in anydesired manner.

Mounted for rocking movement on member I43 is a sleeve-like backingmember I44 which is provided with a lug I45 and an actuating link I45.

Members I42 and I44 are respectively provided with mating teeth I41 andI48, which, when disposed in the position shown in Figure 1, hold memberI42 in its forward position and the lat ter, acting through fork H4 andthe throwout mechanism holds the clutch parts in automatic position. Aring I49 adjustably threaded on member I43 abuts the rear end of memberI44 and prevents it from shifting axially.

Accordingly, when link I46 is actuated to rock member I44 so as to bringits teeth E48 into intermeshing relationship with teeth I41 member I42may move rearwardly and in turn allow springs 51 to force the clutchplates into driving engagement. The clutch may therefore be engaged whenthe driving member is operating below the centrifugally engaging speedof the weights or is stationary.

Operation of the clutch takes place in the following manner: As drivingsleeves I2 and I3 and flywheel 25 are accelerated, weights 56 tend toswing or rock outwardly about their knifeedges 18 as axes in response tocentrifugal force. The weights are yieldingly restrained against thistendency by the hold-back assemblies and by the influence of balls 26acting upon sleeve I23. When flywheel 25 has been accelerated to aspeed. predetermined by the mass of weights 66, the strength of springs53 and I29, which are dictated by the operating characteristics desiredin the particular installation involved, weights 66 overcome therestraining action of balls I26 and springs I29 and rock outwardlycomparatively rapidly causing sleeve I23 to move to the left. As thisoccurs, reaction faces 16 of heads 52 fulcrum and slide on the face ofplate 41, and knife edges 18, by virtue of their engagement andfullcruming action upon the flat bottom surfaces of recesses 63 inautomatic plate 31, force automatic 4 bring the facing thereof intocontact with the flywheel face.

After the driven member is frictionally clamped or gripped betweenautomatic plate 31 and flywheel 25 in the manner just described,movement of plate 31 is substantially arrested, and further rockingmovement of weightsv 66 causes faces 16 of heads 32 to force reactionplate 41 away from the flywheel against the action of springs 51 andhold-back springs 53. Movement of plate 41 in this manner causespressure to build up in springs 51 and a corresponding pressure is builtup between the edges 18 of heads 62, and the bottoms of the recesses inautomatic plate 31 with the result that pressure is built up between thefrictional faces of the driving and driven members and shaft I I ispicked up smoothly and without shock. When the pressure builds up to apredetermined value, the plates are brought into non-slippingengagement. As the speed further increases, the pressure builds up,further, and when flywheel 25- attains a predetermined speed, weights 66rock into contact with arcuate faces I31 provided on rim portions I38which are formed on reaction plate 41. In

order to stop weights 66 in a definite plane that is r normal to themechanism, and thus insure dynamic balance of the mechanism, stop-edgeson faces I39 are accurately formed on weights 66 for cooperation withfaces I31. When the weights have moved into their outermost positionswith their faces I39 in contact with faces I31, further acceleration offlywheel 25 is ineffective to cause a further pressure to be built upbetween the plates. The plates are thereby held in non-slippingengagement under a predetermined pressure, and a positive frictioncoupling exists between the driving and driven shafts.

When flywheel 25 is decelerated to a predetermined speed, springs 53force the reaction and automatic plates towards each other which resultsin weights 66 rocking inwardly and causing sleeve I23 to move to theright to a position where balls I26 snap into groove I24 formed insleeve I23.

In View of the resilient nature of the backing means for the reactionmember, should certain weights 66 swing farther outwardly than theremaining weights during the engaging operation, the pressure exerted bythem is nevertheless uniformly distributed about the area of plate 3'!for the reason that reaction plate 41 can tilt or float, and take aslight angular position with respect to automatic plate 31, due to thefact that the sole movement limiting means of the reaction member isconstituted by bolts 48, and the latter are designed to providesufficient play or clearance to permit this tilting action.

When the automatic engaging operation just described is taking place,reaction plate 41 and its associated parts are moved to the left of thepositions in which they are shown in Figure 1. Movement of reactionplate 41 to the left causes the inner ends of fingers 88 to tend to movefrom their cooperating engagement with the face of the bearing assembly,thereby relieving the throwout bearing assembly of substantially allpressure.

When flywheel 25 is decelerated, the automatic disengagement of theclutch occurs in a converse manner to the engaging operation justdescribed and sleeve I23 is moved to the right with balls I26 snappedinto groove I24 as previously explained.

Manual disengagement of the clutch may be effected in the followingmanner: When the plates have been automatically brought into fulldriving engagement in the manner previously described, shaft II 5 may beoperated to displace throwout bearing assembly and the inner ends oflevers 88 to the right of the positions in which they are shown inFigure 1. Movement of levers 88 in this manner causes them to fulcrumabout and react against bolts 82 and withdraw the reaction plate fromthe flywheel. Withdrawal of the reaction plate produces withdrawal ordisengagement of automatic plate 3! from the driven member since plates31 and A! are held in unitary relation by the hold-back assemblies. Ifthe engine speed is maintained above the predetermined engaging speedduring the manual declutching operation, weights 56 remain in theiroutermost positions; therefore, the declutching operation does notinvolve retracting the weights against the action of centrifugal force,which, at high speeds might be sufficiently high to preclude affectingthe manual declutching opera tion, if the latter involved retracting theweights.

Referring now to Figure 3, I haveshown a modified form of clutch whichdoes not embody a latch mechanism.

Threaded into reaction plate 4'! at circumferentially spaced points area plurality of shouldered bolts 58 whose heads 60 lean against the outersurface of cover 38. Bolts 58 preferably extend through springs 51 so asto maintain them in place and as seen in Figure 3, bolts 58 are of alength sufficient to hold the parts in automatic position when thedriving member is operating at idling speed or is stopped.

It is, accordingly, unnecessary to employ a releasable latch mechanismwith this form of the invention, which however, does not permit theclutch to be engaged when the driving shaft is operating at idling speedor is stopped. Also, when the clutch centrifugally engages, reactionplate 41 is forced to the left, thereby causing the heads of bolts 58 tomove out of contact with cover 38.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. In a clutch, a driving member, a driven member, centrifuge-11yoperable means associated with said driving member for bringing saiddriving and driven members into engagement when said driving memberattains a predetermined speed, a cover member mounted on said drivingmember and axially spaced therefrom, said driving member and said coverhaving axially aligned apertures, the walls of said apertures formingbearing surfaces, a sleeve mounted for sliding axial movement in saidapertures, and means operably connecting said centrifugally operablemeans to said sleeve.

2. The clutch described in claim 1, together with means for yieldinglyrestraining said sleeve against movement out of a predetermined axialposition.

3. In a clutch, a driving member, a driven I member, a plurality ofspeed responsive elements for effecting engagement of said members whensaid driving member attains a predetermined speed, an axially movablesleeve supported by said driving member and having outwardly strucktongues engaging said speed responsive elements to insure synchronousoperation thereof, said driving member having at least one bore openingon said sleeve, a ball detent disposed in said bore and having meansurging it into contact with said sleeve, said sleeve having a depressedportion designed to receive said detent when said elements are disposedin retracted position, so that said detent is effective to exertretarding forces on movement of said sleeve and delay operation of saidspeed responsive elements.

4. In a clutch, driving and driven members mounted for engagement anddisengagement, a reaction member operatively associated with saidmembers, a plurality of centrifugally operable levers acting againstsaid driving member and reacting against said reaction member, forforcing said driving and driven members into engagement when one of saidmembers attains a predetermined speed, said reaction member beinggenerally annular in form to provide a central aperture, a sleevemounted for axial sliding movement in said central aperture of saidreaction member, means for connecting said levers to said sleeve, forcontrolling the operation thereof, a plurality of throw-out leversconnected to said reaction member and extending through apertures insaid sleeve, and a throw-out device mounted for axial sliding movementwithin said sleeve and cooperating with the inner ends of said throw-outlevers.

5. The clutch described in claim 4, wherein said means for connectingsaid levers to said sleeve comprises a plurality of tongues provided onsaid sleeve, and seating in recesses provided in said levers.

6. The clutch described in claim 4, wherein the portion of said sleevewhich slides in the central aperture of said reaction member is proforyieldingly restraining said levers against clutch engaging movement;means cooperating with said one driving member for disengaging saidmembers without disturbing the relationship between said retarding meansand said centrifugally operable levers; and means acting upon said onedriving member for bringing said driving and driven members intoengagement independently of said eentrifugally operable levers,

and Without disturbing the relationship between 10 the latter and saidretarding means.

JOSEPH E. PADGETI.

